1. Field of the Invention
The invention relates generally to a planetary gearset of an automatic transmission for a motor vehicle. More particularly the invention pertains to a planet pinion carrier of the planetary gearset.
2. Description of the Prior Art
An automatic transmission may be used in an automotive powertrain with a large diesel engine having a high torque capacity engine of about 700 lb-ft, and with a smaller gasoline engine having a lower torque capacity of about 400 lb-ft. With such a dramatic difference in torques, the carrier of a planetary gear set for the transmission, such as a Ravigneaux gearset, must be able to accommodate a variable number of planet pinions, the number being compatible with the torque capacity of the engine.
Generally the pinions of Ravigneaux gearset require installation from the inside out. Inside-out installation requires manual assembly or a complicated automated assembly process that risks quality and cost.
Other known techniques for dealing with a wide range of torque capacity in a planetary gearset involve using multiple gear sizes and multiple numbers of gear teeth to provide torque capacity flexibility. These features require additional investment cost and packaging changes.
A need exists in the industry for a pinion carrier that can accommodate a wide range of torque capacity by using either six or eight pinions, each pinion having the same size and number of teeth. Preferably the carrier can be integrated with a rocker one-way clutch to minimize production and assembly cost.